CVE-2026-105306 Keycloak-services: keycloak-services: token introspection audience bypass via dynamic client registration
Attackers with an Initial Access Token can bypass audience checks to view sensitive identity and session data from other applications.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-105306?
CVE-2026-105306 is a medium-severity missing authorization vulnerability in Red Hat Build of Keycloak, published on 5 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A flaw was found in the Dynamic Client Registration flow of the Keycloak identity and access management server. The issue occurs because the registration process fails to filter security-sensitive client attributes when a new client is created. An attacker with a valid Initial Access Token can register a client that bypasses audience checks during token introspection. This allows the attacker to view sensitive identity information, roles, and session details from access tokens belonging to other applications in the same realm.
Weakness: CWE-862
Which versions are affected by CVE-2026-105306?
How do I fix CVE-2026-105306?
No fix has been published for CVE-2026-105306 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-105306 being exploited?
There is no known exploitation of CVE-2026-105306 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-q5jp-7g4g-ch69.